Hey everyone, I've been thinking about this a lot lately because last semester in bio lab we were messing around with respiration rates in different conditions, and it got me wondering—how exactly does that step where pyruvate turns into acetyl-CoA affect the total energy you get out of the whole process? Like, I remember glycolysis gives a little ATP, but then this bridge thing happens before the Krebs cycle kicks in, and if it messes up or something, does that tank the overall yield big time? Back when I was cramming for midterms, I kept mixing it up with just the cycle itself, but now I'm curious how crucial that conversion really is for squeezing out max energy from glucose. Anyone got a clear take on it?
6 Views
Yeah, that pyruvate to acetyl-CoA step is kind of a quiet game-changer. From what I've seen in my own notes and double-checking stuff, it doesn't spit out ATP directly, but it sets everything up by feeding acetyl-CoA into the Krebs cycle while also tossing out an NADH per pyruvate. That NADH later helps crank out more ATP through the electron transport chain, so skipping or blocking that link would mean way less total energy—probably dropping the yield a bunch since you're not getting those extra reducing powers for oxidative phosphorylation. I always thought it was neat how it's this obligatory mitochondrial handover after glycolysis in the cytosol. If you're trying to visualize the whole pathway flow, I sometimes refer back to cellular respiration chart just to remind myself of the sequence without getting lost in details. In my experience, once you see how that acetyl-CoA entry ramps up the downstream NADH and FADH2, the big energy payoff makes more sense.